Electrical smelting process.



No. 814,050. PATENTBD MAR. 6, 1996.

W. McA. JOHNSON. ELECTRICAL SMBLTING PROCESS.

APPLICATION FKLBD MAY 24, 1904 Lil UNITED l ATE NT OFFICE.

Specification of Letters Patent.

Patented March 6, 1906.

Applicatitn filed May 24, 1904. Serial No. 209,998.

To alt whom it may concern:

Be it known that I, WOOLSEY MoA. JOHN- son, a citizen of the United States, residing at Iola, in the county of Allen and State of Kansas, have invented certain new and useful Improvements in Electrical Smeltin Processes, of which the following is a s eci motion.

This invention is a process 0 electrically smelting ores, and is more particularly adapted for electrically smelting ores of zinc containing iron or other substance which is liable to flux or otherwise injure the walls of the retort. Accordin to my invention, the charge is so disposed wit in the retort and the opera tion is so conducted as to substantially prevent injury of the retort by the action of constituents of the ore.

For a full understanding of my invention reference is made to the accompanying drawings, showing a convenient form of furnace for carrying out my process.

Figure I re resents in longitudinal vertical section' an e ectrically-heated zinc retort, and Fig. 2 is a transverse vertical section of the same on line II H of Fig. 1.

Referring to the figures, 1 represents a suitable furnace or retort, which ma be constructed of fire-clay or other suitab e refractory material. As shown, this retort comprises a closed chamber, the end walls 2 of which consist of blocks or doors having sub stantially the same cross-section as the fur mace-chamber and are luted therein, as indicated at 3 3. An outlet 4 is provided for the volatile roducts of the reaction.

The e ectrical connections to the charge are referably made through the side Walls of t e retort. For this purpose carbon or graphite blocks 5 6 are set in the side walls of the furnace near its ends, the inner faces of said blocks being substantially flush with the inner faces of the walls. (onductors 7 7, which may be of graphite or of metal, are secured to these blocks and extend outwardly through the furnace-walls for connection to the external circuit. The blocks 5 6 and the conductors 7 are luted in place, as indicated at 8, suitable luting for this purpose consisting of a mixture of water-glass and graphite. As more clearly shown in Fig. 2, the carbon blocks 5 6 are arranged in o positely-disposed pairs, one of these pairs being located near each end of the retort. The blocks 5 5, constituting one pair, are electrically connect ed to one pole of a suitable generator by a conductor, as indicated at 9, the other pair being connected by the conductor 10 to the other pole of the generator. The furnace may be charged through the ends or any suitable charging-openings may be provided.

In charging the furnace I first distribute over the hearth a layer 11 oi refractory ma terial, which may be acid,neutral or basic. in accordance with the character of the charge and the material of the retort. For instance, silica, high-grade fire-clay, or bauxite may be used. Over this layer and extending across the furnace between the carbon blocks 5 5 and 6 6, constituting each of the pairs above mentioned, I arrange a body of con ductive carbon, which may be in the form of rods, blocks, or plates of carbon or graphite. I prefer, however, to use the carbon in the form of a loose mass of conductive coke. These bodies oi coke are indicated at 12 12 and constitute the active electrodes, the current traversing the furnace charge between said bodies. The blocks 5 6 serve to establish eiiective electrical contact with the removable electrodes 12 12. Above the layer 1} and extending upward against the side walls of the furnace, as indicated in dotted lines in Fig. 2, l arrange a body of in hgrade ore 13, mixed with high-resist some on e. I may use for this portion of the charge a roasted zinc ore containing eighty to ninety per cent. zinc oxid with small percentages of iron, lime, and lead, mixed with eight to ten mesh coke, together with suiiicient fine coke to serve for the reduction. Above and within this high-resistance portion of the charge I place the main furnace char e 14, consisting of a low-grade ore containing hit to seventy per cent. of zinc oxid, fifteen to thirty per cent. of iron, and smaller proportions of lime, lead, copper, &c., this low rade orc being mixed with coke to form a c large of relatively low resistance. Both high and low resistance portions of the charge are in operative electrical contact with the electrodes 12 12. The charges should he so distributed and of such composition that the heat throughout the furnace is sui'istautially uniform.

In operation the current passes through the charge between the electrodes l2 l2, raising it to the temperature required for smelting. The portion 13 oi the charge, consisting of in h-grade ore containing little iron, is in capable of injuriugthc retort and serves to effectively protect the retort from the. super posed charge 14 of low-grade ore. "lhc retort is further guarded against injury by the refractory layer 1 1. Alt er the smelting op eration is cmnpleted one or both of the end walls may be removed for the withdrawal of the residue and the introduction of a fresh charge, the electrodes 12 12 being used repeatedly with such addition of fresh material as may be required.

The furnace here illustrated is claimed in my copend ing application, Serial No. 209,997, filed May 24, 1904.

I claim- 1. The smelting process, which consists in interposing between a charge containing lowgrade ore, and a furnace-wall, a charge containing high-grade ore, thereby protecting said wall from the actionof said low-grade ore, substantially as described.

.2. The smelting process, which consists in interposing between a charge containing lowgrade ore, and a furnace-wall, a charge containing high-grade ore and a layer of inert material, thereby protecting said wall from the action of said low-grade ore, substan tially as described.

3. The electrical smelting process, which consists in interposing between a low-resistance charge containing low-grade ore, and a furnace-wall, a high-resistmiee charge containing high-grade ore, thereby protecting said wall from the action of said low-grade ore, and transmitting an electric current through said charge, substantially described.

4. The electrical smelting process, which consists in interposing between a low-resistance charge containing lowgrade ore, and a furnace-wall, a high-resistance charge containing high-grade ore and a layer of inert material, thereby rotecting said wall from the action of said ow-grade ore, and transmitting an electric current through said charge, substantially as described.

5. The electrical smelting process, which consists in arranging. on'a suitable hearth a body or charge of relatively high electrical resistance, arranging upon said body or charge a charge of lower electrical resistance, and transmitting an electric current through said charges, substantially as described.

6. The electrical smelting process, which consists in arranging on a suitable hearth a body or charge of relatively high electrical resistance, arranging upon said body or charge a charge of lower electrical resistance, transmitting an electric current through said charges, said charges being so arranged as to secure a substantially even temperature within the furnace, substantially described.

7. The electrical smelting process, which consists in arranging on a suitable hearth a layer of inert material, arrangingon said layer a body or charge of relatively high electrical tance, arranging upon said bodyor charge a charge of lower electrical resistance, and transn'iitting an electric current through said charges, substantially as described.

8. The electrical smelting process, which consists in interposing between bodies of divided carbon constituting the electrodes a suitable conductive charge, and passing an electric current through said charge, substantially as described.

9. The process of recovering volatile metals, which. consists in interposing between bodies of divided carbon a suitable conductive charge containing a volatile metal, and passing an electric current through said charge, substantially as described.

10. The process of recovering zinc, which consists in interposing between bodies of divided carbon constituting the electrodes a suitable conductive charge containing zinc, and passing an electric current through said charge, substantially as described.

11. The electrical smelting process, which consists in interposing between bodies of divid ed carbon a conductive charge comprising a lower layer of hi h-grade ore and an upper layer of relatively ow-grade ore, and passing an electric current through said charge, substantially as described.

12. The electrical smelting process, which consists in interposing between bodies of divided carbon a charge comprising a lower layer of highgrade ore mixed with high-resistance-carbon and an upper layer of lowgrademre mixed with low-resistance carbon, and passing an electric current through said charge, substantiall r as described.

13. The process 01 smelting zinc ores, which consists in inter osing between a charge con taining low-gra e zinc ore and a furnace-wall, a charge containing high ade zinc ore, thereby rotecting said wall om the action of said lbw-grade ore, substantially as described.

In testimony whereof I aflix my signature in presence of two Witnesses.

VVOOLSEY MoA. JOHNSON.

Witnesses:

JOHN H. SIGGERs, JULIA B. HILL. 

